With Rx, how do I ignore all-except-the-latest value when my Subscribe method is running

Question

Using Reactive Extensions, I want to ignore messages coming from my event stream that occur while my Subscribe method is running. I.e. it sometimes takes me lon

Answer 1

An example using Observable.Switch. It also handles the case when you complete the task but there is nothing in the queue.

using System.Reactive.Linq;
using System.Reactive.Subjects;
using System.Reactive.Concurrency;
using System.Reactive.Disposables;

namespace System.Reactive
{
    public static class RXX
    {
        public static IDisposable SubscribeWithoutOverlap
        ( this IObservable source
        , Action action
        , IScheduler scheduler = null)
        {
            var sampler = new Subject();
            scheduler = scheduler ?? Scheduler.Default;
            var p = source.Publish();
            var connection = p.Connect();

            var subscription = sampler.Select(x=>p.Take(1))
                .Switch()
                .ObserveOn(scheduler)
                .Subscribe(l =>
                {
                    action(l);
                    sampler.OnNext(Unit.Default);
                });

            sampler.OnNext(Unit.Default);

            return new CompositeDisposable(connection, subscription);
        }
    }
}